1. Field of the Invention
The present invention relates to manufacturing interlocked stacks of laminations, and more particularly to a method of making and shaping an interlocked lamination stack.
2. Description of the Related Art
Conventionally, laminations are used to construct interlocked laminated cores for electromagnetic devices such as stator and rotor cores, transformer cores, electromagnet cores, ignition cores, and the like. Such cores may be cylindrical, square, rectangular, pencil shaped and the like. Each of these cores has a stacking axis along which the laminations are stacked, i.e. the direction of stacking, and a stack or core axis. Laminated interlocked cylindrical stator and rotor cores and square or rectangular cores are constructed such that the plane of each lamination is substantially perpendicular to both the core axis and the stacking axis since the core and stacking axes are coaxial. Such cores and the method of making them are described in my U.S. Pat. Nos. 4,738,020 and 6,131,268, the disclosures of which are hereby expressly incorporated herein by reference. The laminations of a cylindrical pencil core such as is shown in my U.S. Pat. No. 6,163,949 are oriented with the plane of each of the lamination(s) substantially parallel to the core axis and substantially perpendicular to the stacking axis. The disclosure of my U.S. Pat. No. 6,163,949 is hereby expressly incorporated herein by reference.
In such prior art cores, each lamination is typically blanked from sheet stock material. The sheet stock material is fed through a series of punching stations in a progressive die to progressively form the laminations. The shape of each lamination may be individually controlled by a controller so that laminations may be provided with different features. Once a lamination has passed through all the punching stations of the progressive die, the lamination is blanked or separated from the carrier sheet stock material. In the last station of the progressive die, the laminations are received in a choke wherein they are stacked and interlocked.
One of the punching stations forms interlock features into each lamination. Interlock tabs are pushed out of the plane of the lamination leaving an interlock slot therein. At the stacking station the interlock tabs of one lamination are received in such interlock slots formed in the previously blanked lamination as the laminations are stacked. The interlock tabs are pressed into the interlock slots by staking punches, which form a part of the blanking station, to secure the, laminations to one another.
The conventional prior art method of producing laminated cores described above utilizes laminations which are all positioned in mutually parallel orientations and the overall final shape of the core is fixed and predetermined by the shape of the individual laminations. Such prior art cores are rigid and have a final fixed shape.
It is desired to provide a method and apparatus for constructing a stack of interlocked laminations wherein the shape of the stack is not fixed and may be determined after the interlocked stack is formed.